That said, there isn't really such thing as a better respected A level - well, depending on who you're trying to impress. General studies however is always a no-no.
Biology is respected by universities, especially since it is a science. But Music A Level is really hard and is a niche subject. Plus people forget that there are lot of drama/music/dance unis that take those A Levels very seriously. You can study hard and do well in science, but you got to work hard as well as a have talent when it comes to an art subject.
The most respected A Level of all time however has got to be Mandarin Chinese or Japanese. Then perhaps Physics and Further Maths.
Doesn't it depend on who you are trying to impress or your goal at the end of it?
A music school is obviously going to think Music is top priority where as Biology may be completely irrelevant. But if you were applying for say Medicine or something related, then the most respected may be Biology with perhaps Media Studies being least respected.